Poultry operations incubate fertilized eggs in incubators to increase the production of poultry for breeding and food supplies. Generally, the eggs are placed in a setter tray in a substantially vertical orientation. The setter trays are then placed in an incubator throughout an 18 day portion of an incubation period. The trays are periodically tilted and rocked throughout the incubation period to prevent the developing embryos from adhering to the interior egg shell surfaces. The environment--temperature, humidity, etc. within the incubator is regulated to promote uniform embryo development by attempting to simulate or even improve upon natural incubation conditions. Upon the completion of the 18 day portion, the setter trays are removed from the incubator. The eggs are then transferred to hatcher trays designed to facilitate and support chick hatches.
Hatcher trays typically support an egg in a horizontal orientation throughout a hatching portion of the incubation period. Unlike the setter tray receptacles which restrict egg movement, hatcher trays attempt to provide sufficient room for the eggs during the hatch to minimize injury to the chicks. Once the eggs are transferred from the setter trays, the hatcher trays are placed in a temperature controlled hatcher. Over the next two to three day period, the chicks hatch from the eggs and occupy a substantial portion of the provided room. The hatcher trays and chicks are then removed for further processing.
Alternative tray designs have been proposed to promote the efficient use of incubator space. One such proposed setter tray supports eggs in a vertical array having a tower-like structure rather than in a horizontal array of a typical pan-like tray. Other trays purport to simplify the transfer of eggs from the setter to the hatcher trays. One such proposed design utilizes a setter tray sized to fit within a corresponding hatcher tray. Once the trays are properly fitted, the bottom of the setter tray slides open to deposit the incubated eggs onto the bottom of the hatcher tray in a horizontal orientation. Thereafter, the setter tray is removed and the hatcher tray is then placed into a hatch chamber for the requisite period.
Another proposed design includes a compartmentalized tray which attempts to minimize the handling of eggs between incubation and hatching periods. The tray includes both a body member and a cover. The body member includes slotted sidewalls integrally formed with the lower surface of a top wall. The sidewalls extend downwardly when in incubation orientation, and upwardly when in hatch orientation.
The lower surface of the top wall includes a large number of egg shaped oval compartments as well as perforations within the compartments to promote the free circulation of air. The dimensions of the compartments are intended to be sufficient to allow a hatching chick to extricate itself from its shell when hatching.
Four short upright fingers having rounded upper ends are integrally formed on the upper surface of the top wall. A group of fingers is centered over each compartment to support the smaller egg ends in coaction with the cover, when the body and cover are assembled in a stacked relationship.
The cover includes a horizontal wall and a skirt. The skirt acts to space the cover from the upper surface of the body member, when in a stacked relationship, at a distance at least greater than the length (major dimension) of the eggs intend to be handled. The horizontal wall defines a series of circular openings of a diameter slightly greater than the diameter (minor dimension) of an egg to be handled so that each egg will be supported around its "waist". Additionally, each opening is centered over the four fingers carried by the top wall of the next lower tray body and also below the corresponding compartment of its own tray body, when in a stacked relationship.
In use, a tray body is first placed onto a support, in its incubation orientation, to act as a base. A cover portion is placed atop the body. A plurality of eggs are then placed, with their major axis vertical, into each of the circular openings so that the smaller egg end is supported by the four fingers carried by the top wall of the next lower body. This process is repeated until a stack of fully loaded tray bodies and covers is created. Thereafter, the stack of trays is placed into an incubator for an eighteen or nineteen day incubation period. The stack is rhythmically tilted within the incubator to prevent the adhesion of the embryos to the interior egg shell surfaces throughout this period.
After eighteen or nineteen days, a computer actuated tray tilting mechanism arrests the rhythmic tilting motion of the stack by placing the stack in a horizontal position. Thereafter, the stack is completely inverted to drop each egg from its circular opening into the corresponding compartment in the top wall of the next lower body member. During the inversion process, complete emergence of each egg from its circular opening is said to be guaranteed by the fact that the cover and body member walls are spaced apart by a distance greater than the length of an egg.
Once the inversion of a stack is complete, each egg is supported in the compartments in a horizontal orientation throughout the two or three day hatching period. Once hatching is complete, the chicks are contained within the compartments until the trays--still stacked and inverted, are removed from the incubator and disassembled.